Conventionally, furniture such as display cabinets, storage cabinets, cupboards, and desks; home electric appliances such as refrigerators, washing machines, air-conditioners, mobile phones, and personal computers; surfaces of base materials composed of woody materials including wood, plywood, laminated wood, particle boards, and hard boards, to be used as building components for floors, walls, bath rooms, and the like; and surfaces of base materials composed of metallic materials including iron and aluminum; are decorated by lamination with decorative sheets to provide products for use. Decorative sheets are required to have not only decorative properties, but also high levels of scratch resistance, abrasion resistance, stain resistance, and the like in a well-balanced manner.
For imparting the properties described above to a decorative sheet, formation of a resin coating on the surface of the thermoplastic resin film to be used as the base material is widely carried out by application of a resin composition coating material. However, there is a problem that coating streaks are easily formed during the application of the coating material on the base material. In particular, coating streaks tend to be serious problems in cases where a polyolefin-based resin film, polyester-based resin film, or the like is used as the thermoplastic resin film. There is also a problem that, since a resin coating composed of a resin composition coating material has low extensibility, deformation of the decorative sheet tends to cause cracking of the resin coating during application of the decorative sheet to membrane press forming, vacuum pressure forming, or the like.
In order to solve these problems, “a method for producing a polyvinyl chloride sheet for membrane press forming, comprising pressing a preheated first polyvinyl chloride sheet on a heating drum, further pressing at least one additional layer of preheated polyvinyl chloride sheet thereon, further pressing a transfer film thereon, and then sending the resulting sheet to a design-imparting roll, wherein the transfer film has a structure in which a polyester film, a release coating layer, a resin coating layer, and a hot-melt coating layer are laminated with each other in this order from the outer-layer side” has been proposed (Patent Document 1). However, this technique was also insufficient especially for achieving high-gloss, mirror-like finish.